JP2017131004A - Non-contact power reception device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power reception device for suppressing generation of harmonic noise.SOLUTION: A non-contact power reception device comprises: a power reception coil that in a non-contact manner, receives AC power supplied from a power transmission device; a resonant circuit that includes the power reception coil and a resonant capacitor and resonates with a frequency of the AC power; a diode full-wave rectification circuit that at a first and second input ends, receives input of AC power from the resonant circuit and outputs DC power between an output end and a reference potential end; a common mode filter that includes a first coil and second coil that are wound around a common magnetic material in parallel, in the same direction, and with the same number of turns, the first coil's one end being connected to the output end of the diode full-wave rectification circuit, the second coil's one end being connected to the reference potential end; a smoothing capacitor connected between the other end of the first coil of the common mode filter and the other end of the second coil; and a load connected in parallel to the smoothing capacitor.SELECTED DRAWING: Figure 2

Description

Embodiments described herein relate generally to a contactless power receiving device that receives power from a power transmitting device in a contactless manner.

In recent years, contactless power supply systems that supply power without contact have become widespread. The non-contact power supply system supplies power to a power receiving device such as a mobile terminal or a tablet terminal in a non-contact manner using electromagnetic coupling such as electromagnetic induction or magnetic field resonance. In general, a non-contact power supply system includes a power transmission device and a power reception device, and the power transmission device includes a power transmission circuit and a power transmission coil for supplying power. On the other hand, the power receiving device includes a power receiving coil for receiving power from the power transmitting device in a non-contact manner, a voltage conversion circuit that uses the received power for driving the power receiving device itself, and a secondary battery mounted on the own device. A charging circuit for charging is provided.

  In the non-contact power supply system, it is necessary to increase the Q values of the power transmission coil and the power reception coil in order to supply power to the power reception device even if the power transmission device and the power reception device are separated by 1 to 2 cm or more. For this reason, a frequency (for example, 6.78 MHz or 13.56 MHz) of several MHz or higher that can increase the Q value of the coil is used as the frequency of the AC power output from the power transmission device. When the Q value of the coil is increased, even if the distance between the power transmission coil and the power reception coil is increased, a characteristic capable of supplying power efficiently can be obtained.

  Moreover, the power receiving device can efficiently receive the AC power output from the power transmitting device by configuring the LC resonant circuit with the power receiving coil and the resonant capacitor and designing the impedance of the LC resonant circuit to be low. The AC power supplied to the power receiving device is converted into DC power by the rectifier circuit. The electric power converted into a direct current by the rectifier circuit is converted into a voltage necessary for driving the own machine by the voltage conversion circuit and used.

  Incidentally, a diode full-wave rectifier circuit is generally used as the rectifier circuit, but the diode full-wave rectifier circuit generates harmonic noise because the diode includes the junction capacitance Cj. That is, the equivalent circuit when a reverse voltage is applied to the diode is 0. It can be simulated as a configuration in which a resistance of several Ω and a junction capacitance Cj (capacitor) of several tens of pF are connected in series.

  For this reason, immediately after the switching in which the reverse voltage is applied from the state in which the forward voltage is applied to the diode, the junction capacitance Cj of the diode is rapidly charged, and a large current flows in a short time to generate harmonics. Noise will be generated. The generated harmonic noise is radiated from a power receiving coil of the power receiving device.

  In a non-contact power feeding system that can feed power to the power receiving device even if the power transmitting coil and the power receiving coil are separated by several centimeters or more, since the power receiving coil is not tightly coupled to the power transmitting coil, harmonic noise is generated from the power receiving coil. The contained electromagnetic wave is easily radiated into the space. Therefore, in order to reduce the electromagnetic wave including the harmonic noise output from the power receiving coil, it is necessary to reduce the harmonic noise generated from the diode full-wave rectifier circuit.

  As an example of measures against harmonic noise of a power receiving device, a wireless power receiver as disclosed in Patent Document 1 is known. In the power receiving apparatus of Patent Document 1, a band stop filter circuit is provided between a diode full-wave rectifier circuit and a smoothing capacitor so as to electrically insulate radiation from the rectifier.

  However, it is difficult for the capacitor of the band stop filter circuit to function in the same manner as the junction capacitance Cj of the diode of the rectifier and reduce the harmonic noise. In addition, when the capacitor of the band stop filter circuit is made as small as possible and configured with only an inductor, a large inductor is required for noise reduction. For this reason, it is impossible to supply a sufficient current to the load circuit, and as a result, the output power of the power receiving apparatus decreases.

Special table 2014-53092 gazette

The problem to be solved by the invention is to provide a non-contact power receiving apparatus that suppresses the generation of harmonic noise.

  A contactless power receiving device according to the embodiment includes a power receiving coil that receives AC power supplied from a power transmitting device in a contactless manner, a power receiving coil and a resonance capacitor, and a resonance circuit that resonates at a frequency of the AC power, A full-wave diode rectifier circuit that inputs AC power from the resonance circuit to the first and second input terminals and outputs DC power between the output terminal and the reference potential terminal, and a common magnetic material in parallel in the same direction Including a first coil and a second coil wound by the same number of turns, one end of the first coil being connected to an output end of the diode full-wave rectifier circuit, and the second coil being connected to the reference potential end A common mode filter having one end connected thereto, the other end of the first coil of the common mode filter, a smoothing capacitor connected between the other ends of the second coil, and a load connected in parallel to the smoothing capacitor Equipped with a.

The block diagram which shows the structure of the non-contact electric power feeding system which concerns on one Embodiment. The circuit diagram which shows the structure of the non-contact power receiving apparatus which concerns on one Embodiment. The block diagram which shows schematically the common mode filter used for the non-contact power receiving apparatus of one Embodiment. The characteristic view which shows the impedance and frequency characteristic of the common mode filter used for the non-contact electric power receiving apparatus of one Embodiment. The simulation waveform figure of the conduction current of the diode full wave rectifier circuit used for the non-contact power receiving device of one embodiment. The simulation waveform figure of the conduction current of the diode of the diode full wave rectifier circuit in the conventional non-contact power receiving device. The circuit diagram explaining the structure of the non-contact power receiving apparatus which concerns on 2nd Embodiment. The circuit diagram explaining the structure of the non-contact power receiving apparatus which concerns on 3rd Embodiment. The circuit diagram explaining other composition of the non-contact power receiving device concerning a 3rd embodiment. The circuit diagram explaining another structure of the non-contact power receiving apparatus which concerns on 3rd Embodiment.

  Embodiments for carrying out the invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected about the same location.

(First embodiment)
FIG. 1 is a block diagram illustrating a power feeding system 100 including a contactless power receiving device according to an embodiment. The power supply system 100 includes a power transmission device 10 that supplies power and a power reception device 20 that receives the supplied power in a contactless manner.

  The power transmission device 10 includes a power transmission coil 11, and the power reception device 20 includes a power reception coil 21. The power output from the power transmission device 10 is fed to the power reception device 20 by using electromagnetic coupling such as electromagnetic induction or magnetic field resonance between the power transmission coil 11 and the power reception coil 21.

  The power transmission device 10 is supplied with DC power from a DC power source 12 such as an AC adapter. The power transmission device 10 includes a power transmission circuit 13 that generates high-frequency power, a power transmission coil 11, a voltage conversion circuit 14, an oscillation circuit 15, and a control circuit 16.

  The power transmission circuit 13 converts a direct current into a high-frequency alternating current and outputs the alternating current. The power transmission circuit 13 includes a class E amplifier, or a half-bridge or full-bridge switching circuit. The power transmission circuit 13 performs soft switching by performing zero voltage switching (ZVS) or zero current switching (ZCS).

  Soft switching uses a resonance phenomenon and switches the switching element on and off at the timing when the voltage or current becomes zero. Switching loss can be reduced by zero voltage switching (ZVS) or zero current switching (ZCS). In addition, since the voltage waveform or current waveform changes slowly, switching noise, conduction noise, and radiation noise can be reduced.

  The voltage conversion circuit 14 converts the voltage input from the DC power supply 12 into an appropriate voltage at which the oscillation circuit 15 and the control circuit 16 can operate. For example, the output voltage 24V of the DC power supply 12 is converted into a voltage such as 5V or 3.3V by the voltage conversion circuit 14.

  The oscillation circuit 15 generates a drive signal that controls the switching element of the power transmission circuit 13. The oscillation frequency of the oscillation circuit 15 is the same as or substantially the same as the self-resonance frequency of the resonance circuit composed of the power transmission coil 11 and the capacitor. As the oscillation frequency of the oscillation circuit 15, that is, the switching frequency of the power transmission circuit 13, a switching frequency of several MHz to several tens of MHz is used from the viewpoint of securing a distance of 1 to 2 cm or more between the power transmission coil 11 and the power reception coil 21. . Specifically, a frequency of 6.78 MHz or 13.56 MHz is used.

  If the distance between the power transmission coil 11 and the power reception coil 21 is as short as several millimeters, the configuration of this embodiment can be applied to frequencies of several tens of kHz to several hundreds of kHz. However, the inductance value of the coil and the value of the capacitor used in the switching circuit of the power transmission circuit 13 need to be adjusted according to the frequency.

  The control circuit 16 is a microcomputer including a CPU. The control circuit 16 performs drive control for operating or stopping the power transmission circuit 13 as necessary, communication control with the power receiving device 20, and the like.

  The power receiving device 20 includes a resonance circuit including a power receiving coil 21 and capacitors 22, 23, a diode full-wave rectifier circuit 24, a common mode filter 25, a smoothing capacitor 26, a voltage conversion circuit 27, and a load circuit 28. And a control circuit 29.

  The AC voltage sent from the resonance circuit including the power receiving coil 21 and the capacitors 22 and 23 is converted into a DC voltage by the diode full-wave rectifier circuit 24, and then the DC voltage is smoothed by the common mode filter 25 and the smoothing capacitor 26. The voltage conversion circuit 27 converts the DC voltage smoothed by the common mode filter 25 and the smoothing capacitor 26 into an appropriate voltage at which the control circuit 29 and the load circuit 28 can operate. For example, a smoothed DC voltage of about 40 V is converted into 24 V by the voltage conversion circuit 27 and supplied to the load circuit 28, and converted to 5 V and supplied to the control circuit 29.

  The load circuit 28 is a circuit of an electronic device such as a portable terminal or a tablet terminal, and the power received by the power receiving device 20 is used for operations of the electronic device, charging of a battery built in the electronic device, and the like. The control circuit 29 is composed of a microcomputer including a CPU, and performs drive control for supplying or stopping received power to the load circuit 28 as necessary, communication control with the power transmission device 10, and the like.

  FIG. 2 is a circuit diagram showing a specific configuration of the non-contact power receiving device 20. In FIG. 2, the power receiving device 20 includes a resonant circuit 50 including a power receiving coil 21 and capacitors 22 and 23, and a diode full-wave rectifier circuit 24 connected to both ends of the capacitor 23 on the output side of the resonant circuit 50. Including.

  The diode full-wave rectifier circuit 24 includes diodes 41 to 44, and the anode of the diode 41 and the cathode of the diode 43 are connected to one input terminal 241 of the diode full-wave rectifier circuit 24, and the diode 42 is connected to the other input terminal 242. And the cathode of the diode 44 are connected. The output terminal 243 of the diode full-wave rectifier circuit 24 is connected to one end of the smoothing capacitor 26 via the primary coil 31 of the common mode filter 25, and the reference potential terminal (ground terminal) 244 of the diode full-wave rectifier circuit 24 is The other end of the smoothing capacitor 26 is connected via a secondary coil 32 of the common mode filter 25. A load 60 is connected in parallel across the smoothing capacitor 26. The load 60 includes the voltage conversion circuit 27, the load circuit 28, and the control circuit 29 shown in FIG.

  As shown schematically in FIGS. 3A and 3B, the common mode filter 25 has divided winding and bifilar winding. 3A and 3B, the winding method of the coil is shown on the left side, the equivalent circuit is shown on the right side, and the terminals of each coil are shown by numbers 1 to 4.

  As shown in FIG. 3A, the split winding is obtained by winding two wires around the core 33 separately, and winding the primary side coil 31 and the secondary side coil 32 by the same number of turns. . In the bifilar winding, as shown in FIG. 3B, two parallel lines are wound as they are around the outer periphery of the core 33, and the primary coil 31 and the secondary coil 32 are wound the same number of times. .

  As illustrated in FIG. 3A, the common mode filter 25 includes a differential mode in which currents (represented by solid lines) flow in opposite directions in the coil 31 and the coil 32, and a current (in the same direction in the coil 31 and the coil 32). It operates in the common mode in which the flow (shown by the dotted line) flows.

  The self-resonant frequency of the resonance circuit 50 configured by the power receiving coil 21 and the capacitors 22 and 23 is the same as or substantially the same as the frequency of the high frequency power radiated from the power transmission coil 11 of the power transmission device 10. That is, the self-resonant frequency and the frequency of the high-frequency power are, for example, 6.78 MHz. Then, the power transmission coil 11 of the power transmission device 10 and the power reception coil 21 of the power reception device 20 are electromagnetically coupled to each other, so that power is efficiently transmitted from the power transmission side to the power reception side in a non-contact manner.

  In the positive cycle of the AC power received by the power receiving coil 21 in FIG. 2, the power receiving coil 21 and the capacitors 22, 23 resonate and current flows, and the diode 41, common mode filter from the input terminal 241 of the diode full-wave rectifier circuit 24. The current flows through the coil 31 on the primary side of 25, flows into the smoothing capacitor 26 and the load 60, flows to the coil 32 and the diode 44 on the secondary side of the common mode filter 25, and then returns to the power receiving coil 21 and the capacitor 23.

  In the negative cycle of the AC power fed by the power receiving coil 21, the power receiving coil 21 and the capacitors 22, 23 resonate and current flows, and the diode 42 and the common mode filter 25 1 are input from the input terminal 242 of the diode full-wave rectifier circuit 24. A current flows through the coil 31 on the secondary side, flows into the smoothing capacitor 26 and the load 60, flows through the coil 32 and the diode 43 on the secondary side of the common mode filter 25, and then returns to the capacitors 22 and 23 and the power receiving coil 21.

  As shown in FIG. 3, the common mode filter 25 has a low impedance at a specific frequency and has a low current in the differential mode in which the directions of the currents flowing through the primary coil 31 and the secondary coil 32 are reversed. Easy to flow. In addition, harmonic noise may propagate to the wiring (power supply line or ground line) connected to the load 60, and may wrap around the signal line as common mode noise, which is the same for the primary side coil 31 and the secondary side coil 32. Current may flow in the direction. However, in the common mode, the common mode noise can be suppressed because the impedance of the common mode filter 25 is sufficiently high.

  FIG. 4 is a characteristic diagram showing impedance / frequency characteristics of the common mode filter 25 connected to the subsequent stage of the diode full-wave rectifier circuit 24. 4, the horizontal axis represents frequency, the vertical axis represents impedance, characteristic A represents differential mode impedance, and characteristic B represents common mode impedance.

  In FIG. 4, a point A1 on the characteristic A indicates the impedance of the differential mode at a fundamental frequency of 6.78 MHz. Point A2 indicates the differential mode impedance at a frequency of 20.34 MHz (three times the fundamental frequency). Furthermore, point A3 indicates the differential mode impedance at a frequency of 155.94 MHz (23 times the fundamental frequency). A point B1 on the characteristic B indicates a common mode impedance at a frequency of 47.46 MHz (seven times the fundamental frequency).

  As the behavior of the common mode filter 25, the differential mode impedance suppresses the signal current, and the common mode impedance suppresses the common mode noise. Further, the common mode filter has an effect of canceling out the magnetic field generated by the current of the differential signal of the harmonic noise.

  When the AC power is 6.78 MHz, the output voltage of the diode full-wave rectifier circuit 24 has a voltage waveform of 6.78 MHz. Since the differential mode impedance (A1) at a frequency of 6.78 MHz is as low as about 50Ω, the current passes through the common mode filter 25 without being suppressed. On the other hand, since the differential mode impedance (A2) at the 6.78 MHz third harmonic (20.34 MHz) is as high as 210Ω, harmonic noise can be suppressed. Moreover, the effect of reducing harmonic noise is also obtained by canceling out the magnetic flux in the common mode filter 25. Furthermore, since the differential mode impedance (A3) at the 6.78 MHz 23rd harmonic (155.94 MHz) is increased to about 5500Ω, the effect of suppressing harmonic noise is further increased.

  In addition, when the electromagnetic noise including the harmonic noise is radiated from the power receiving coil 21 without suppressing the harmonic noise, the harmonic noise propagates to the wiring (power supply line or earth line) connected to the load 60 and is signaled. May wrap around the line. For this reason, it may appear as common mode noise. However, as shown by the characteristic B in FIG. 4, the common mode impedance of the common mode filter 25 is sufficiently high in all frequency bands, so that common mode noise can be suppressed.

  Next, the power receiving operation of the power receiving device 20 will be described in detail. FIG. 5 is a simulation waveform of the conduction current of the diode 41 used in the diode full-wave rectification circuit 24. The horizontal axis in FIG. 5 represents time, and the vertical axis represents current. The frequency of the AC power received by the power receiving coil 21 is 6.78 MHz.

  In FIG. 5, point C is a point where the conduction current of the diode 41 switches from a state in which the current flows from the anode to the cathode to a state in which the current flows from the cathode to the anode. Point D indicates a point where the conduction current of the diode 41 switches from a state where the current flows from the cathode to the anode to a state where the current flows from the anode to the cathode.

  In the positive cycle of the AC power received by the power receiving coil 21, as described above, the power receiving coil 21 and the capacitors 22, 23 resonate and current flows, and the diode 41 and the coil 31 on the primary side of the common mode filter 25 are connected. Through the smoothing capacitor 26 and the load 60. Furthermore, after flowing through the coil 33 and the diode 44 on the secondary side of the common mode filter 25, the process returns to the power receiving coil 21 and the capacitor 23.

  On the other hand, at the timing when the AC power fed by the power receiving coil 21 changes from the positive cycle to the negative cycle (point C in FIG. 5), the current flows from the cathode of the diode 41 to the anode. An outline of the conduction current of the power receiving device 20 in this state will be described.

  Normally, a diode does not allow current to flow from the cathode to the anode, but an equivalent circuit when a reverse voltage is applied to the diode has a configuration in which a resistor and a junction capacitor Cj are connected in series. When the AC power is rectified, the current flows from the cathode to the anode by the junction capacitance Cj of the diode 41.

  Therefore, at the timing when the cycle changes from the positive cycle to the negative cycle, the power receiving coil 21 and the capacitors 22 and 23 resonate and current flows, and the smoothing is performed via the diode 44 and the coil 32 on the secondary side of the common mode filter 25. A current flows into the capacitor 26 and the load 60. Furthermore, after flowing through the coil 31 and the diode 41 on the primary side of the common mode filter 25, the flow returns to the power receiving coil 21 through the capacitors 22 and 23.

  The time for the diode 41 to flow from the cathode to the anode is actually short and depends on the size of the junction capacitance Cj of the diode 41. When the junction capacitance Cj is large, the conduction time of the current flowing from the cathode to the anode becomes long, and when the junction capacitance Cj is small, the conduction time of the current becomes short. Therefore, a diode with a small junction capacitance Cj is ideal for reducing harmonic noise.

  In the embodiment, the peak current of the conduction current flowing from the cathode to the anode is suppressed by the common mode filter 25 arranged in series with the diode 41, and a current waveform close to a sine wave is obtained. For this reason, it is difficult to superimpose harmonic components on the current waveform, and the effect of reducing the generation of harmonic noise can be obtained.

  That is, as shown in FIG. 5, the conduction current (Is) during the period in which current flows from the cathode to the anode of the diode 41 (point C → D) is suppressed by the impedance of the common mode filter 25 and is 0.26 A during 43 ns. Current flows, and the current flows in a waveform close to a sine wave. Therefore, the waveform has less harmonic noise.

  Further, in the negative cycle of the AC power received by the power receiving coil 21, as described above, the power receiving coil 21 and the capacitors 22 and 23 resonate and current flows, and the diode 42 and the coil 32 on the primary side of the common mode filter 25. And flows into the smoothing capacitor 26 and the load 60. Further, after flowing through the coil 32 and the diode 43 on the secondary side of the common mode filter 25, the process returns to the capacitors 22 and 23 and the power receiving coil 21.

  Further, at the timing when the AC power received by the power receiving coil 21 is switched from the negative cycle to the positive cycle (point D in FIG. 5), it flows from the cathode of the diode 42 to the anode. At this time, the receiving coil 21 receives AC power, resonates with the capacitor, and an alternating current flows, and flows into the smoothing capacitor 26 and the load 60 via the diode 43 and the coil 32 on the secondary side of the common mode filter 25. . Furthermore, after flowing through the coil 31 and the diode 42 on the primary side of the common mode filter 25, it returns to the power receiving coil 21 via the capacitors 22 and 23.

  At the timing when the AC power is switched from the negative cycle to the positive cycle, the conduction current flowing from the cathode of the diode 42 to the anode is suppressed by the common mode filter 25 arranged in series with the diode 42.

  In FIG. 5, the current flowing from the cathode to the anode due to the junction capacitance Cj of the diode 41 has been described. However, when the current flows from the cathode to the anode in the other diodes 42, 43, and 44, the common mode filter 25 The peak current of the conduction current flowing from the cathode to the anode is suppressed, and a current waveform close to a sine wave is obtained.

  FIG. 6 is a simulation waveform of the conduction current of the diode 41 of the diode full-wave rectifier circuit 24 in the conventional non-contact power receiving apparatus.

  6, the common mode filter 25 is removed from the configuration of FIG. 2, the output terminal 243 of the diode full-wave rectifier circuit 24 is directly connected to one end of the smoothing capacitor 26, and the reference potential terminal 244 is connected to the other end of the smoothing capacitor 26. It is a simulation waveform of the conduction current of the diode 41 in a directly connected circuit. The horizontal axis in FIG. 6 represents time, and the vertical axis represents current. The frequency of the AC power received by the power receiving coil 21 is 6.78 MHz.

  For example, the case where the junction capacitance Cj of the diode 41 used in the simulation is assumed to be 740 pF will be described. The alternating current power fed by the power receiving coil 21 is converted into direct current power by the diode full-wave rectifier circuit 24. When the AC power changes from a positive cycle to a negative cycle, the conduction current of the diode 41 flows from the cathode to the anode. At this time, since there is no common mode filter 25, the conduction current flows without being suppressed.

  In the simulation waveform of FIG. 6, point C is a point where the conduction current of the diode 41 switches from a state in which the current flows from the anode to the cathode to a state in which the current flows from the cathode to the anode. Point D indicates a point where the conduction current of the diode 41 switches from a state where the current flows from the cathode to the anode to a state where the current flows from the anode to the cathode.

  In FIG. 6, a peak current (Ip) of 0.45 A flows for only 15 ns between points C and D. This peak current causes a harmonic in the AC voltage of the power receiving coil 21. Therefore, the power receiving apparatus of the embodiment can reduce the generation of harmonic noise.

Next, with reference to Table 1, the measurement result with an actual machine will be described.

  Table 1 shows the result of simply measuring the noise level emitted from each non-contact power receiving device of the embodiment and an actual device corresponding to a conventional power receiving device as a comparative example. An actual machine corresponding to the conventional power receiving apparatus has a configuration in which the common mode filter 25 is removed from the power receiving apparatus of the embodiment.

  In Table 1, the noise level of the harmonic frequency (3 times, 7 times, and 23 times the fundamental frequency) when the frequency of the AC power to be received is 6.78 MHz is used as the fundamental frequency. The result of calculating the reduction amount from the difference between the values measured in Example) is shown. As shown in Table 1, the noise level reduction amount of the third harmonic (20.34 MHz) is −68 dBm in the power receiving device of the comparative example, whereas the noise level of the power receiving device in the embodiment is −78 dBm. Yes, the embodiment is reduced by 10 dB.

  Similarly, in the seventh harmonic (47.46 MHz), the noise level in the embodiment is −83 dBm, while in the comparative example, it is −65 dBm, and the embodiment is reduced by 18 dB. Furthermore, in the 23rd harmonic (155.94 MHz), the noise level in the embodiment is -91 dBm, whereas in the comparative example, it is -68 dBm, and it is confirmed that the embodiment is reduced by 23 dB. did it.

  As described above, according to the first embodiment, the noise level of harmonics can be reduced.

(Second Embodiment)
Next, the configuration of the non-contact power receiving device according to the second embodiment will be described with reference to FIG.

  The power receiving device 20 of FIG. 7 is an example using a common mode filter 25 in which four coils 31, 32, 33, and 34 are wound around one core by the same number of turns. In FIG. 7, AC power from the resonance circuit is input to the input terminals 241 and 242 of the diode full-wave rectifier circuit 24, and DC power is output between the output terminal 243 of the diode full-wave rectifier circuit 24 and the reference potential terminal 244. In the current path between the cathode of the diode 41 and the output end 243 and the current path between the cathode of the diode 42 and the output end 243, the primary side coil 31 and the secondary side of the common mode filter 25 are respectively connected. A coil 32 is arranged.

  Further, the coil 33 on the tertiary side and the quaternary side of the common mode filter 25 are respectively connected to the current path between the anode of the diode 43 and the reference potential terminal 244 and the current path between the anode of the diode 44 and the reference potential terminal 244. The coil 34 is arranged. The smoothing capacitor 26 is connected between the output terminal 243 and the reference potential terminal 244.

  The configuration of the power receiving device 20 of FIG. 7 is the same as that of FIG. 2 except that the common mode filter 25 is provided with four coils, and the same operations and effects as those of the embodiment of FIG. 2 are obtained.

(Third embodiment)
Next, the configuration of the non-contact power receiving device according to the third embodiment will be described with reference to FIGS. 8, 9, and 10.

  The power receiving device 20 of FIG. 8 inputs AC power from the resonance circuit to the input terminals 241 and 242 of the diode full-wave rectifier circuit 24, and DC power between the output terminal 243 of the diode full-wave rectifier circuit 24 and the reference potential terminal 244. In the current path between the cathode of the diode 41 and the output terminal 243, and the current path between the cathode of the diode 42 and the output terminal 243, the coil 31 on the primary side of the common mode filter 251 The secondary coil 32 is arranged.

  Further, a primary side coil 31 and a secondary side of the common mode filter 252 are respectively connected to a current path between the anode of the diode 43 and the reference potential end 244 and a current path between the anode of the diode 44 and the reference potential end 244. The coil 32 is arranged. The smoothing capacitor 26 is connected between the output terminal 243 and the reference potential terminal 244.

  That is, the power receiving device 20 in FIG. 8 has two common mode filters 25 in the configuration in FIG. 2 and is divided into diodes 41 and 42 and diodes 43 and 44, respectively. The configuration of FIG. 8 is the same as that of FIG. 2 except that two common mode filters 25 are provided, and the same operation and effect as the embodiment of FIG. 2 can be obtained.

  The power receiving device 20 in FIG. 9 inputs AC power from the resonance circuit to the input terminals 241 and 242 of the diode full-wave rectifier circuit 24, and DC power between the output terminal 243 and the reference potential terminal 244 of the diode full-wave rectifier circuit 24. The primary side coil 31 and the secondary side coil 32 of the common mode filter 25 are arranged in the current path between the cathodes of the diodes 41 and 42 and the output terminal 243. The anodes of the diodes 43 and 44 are connected to the reference potential terminal 244, and the smoothing capacitor 26 is connected between the output terminal 243 and the reference potential terminal 244.

  That is, the power receiving device 20 in FIG. 9 is configured such that the common mode filter 25 is disposed only for the diodes 41 and 42 with respect to the configuration in FIG. Since the common mode filter 25 acts on the diodes 41 and 42, it does not function as a differential mode, but acts as a choke coil, so that a harmonic suppression effect can be obtained.

  In addition, the harmonic noise cannot be suppressed, and the harmonic noise may propagate to the wiring (power supply line or ground line), wrap around the signal line, and appear as common mode noise. However, as shown by the characteristic B in FIG. Furthermore, since the common mode impedance of the common mode filter 25 is sufficiently high, common mode noise can be suppressed. Since the common mode filter 25 is not disposed with respect to the diodes 43 and 44, the suppression power of harmonic noise is slightly inferior to that of the configuration of FIG.

  10 receives AC power from the resonance circuit to input terminals 241 and 242 of the diode full-wave rectifier circuit 24, and DC power is supplied between the output terminal 243 of the diode full-wave rectifier circuit 24 and the reference potential terminal 244. The primary side coil 31 and the secondary side coil 32 of the common mode filter 25 are arranged in the current path between the anodes of the diodes 43 and 44 and the reference potential terminal 244. The cathodes of the diodes 41 and 42 are connected to the output terminal 243, and the smoothing capacitor 26 is connected between the output terminal 243 and the reference potential terminal 244.

  That is, the power receiving device 20 in FIG. 10 is configured such that the common mode filter 25 is disposed only for the diodes 43 and 44 with respect to the configuration in FIG. Similarly to the configuration of FIG. 9, the common mode filter 25 acts as a choke coil, so that a harmonic suppression effect can be obtained. Moreover, common mode noise can be suppressed.

  In order to commercialize a non-contact power supply system, it is necessary to satisfy regulatory values for radiation noise and conduction noise (EMI) in each country. Considering a frequency of 30 MHz or less that is regulated by conduction noise or the like, the switching frequency of 6.78 MHz is an ISM (Industry-Science-Medical) frequency internationally, so the regulation value is loose. Moreover, since 13.56 MHz, which is twice 6.78 MHz, and 27.12 MHz, which is four times higher, are also ISM frequencies, the regulations are loose. On the other hand, since 20.34 MHz, which is a triple harmonic, is not an ISM frequency, it is necessary to keep conduction noise and radiation noise low, and the configuration of this embodiment is an effective means for noise reduction.

  The noise radiated from the power transmission device 10 is radiated from the power transmission coil 11 in particular, but is also radiated from the power reception coil 21 during power transmission. Therefore, it is necessary to remove harmonic distortion from the power applied to the power reception coil 21. According to the configuration shown in the embodiment, not only the third harmonic and the seventh harmonic, but also other higher harmonic components can be greatly attenuated, which is effective in reducing noise.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 10 ... Power transmission apparatus 20 ... Power reception apparatus 21 ... Reception coil 24 ... Diode full wave rectification circuit 25 ... Common mode filter 26 ... Smoothing capacitors 41-44 ... Diode 50 ... Resonance circuit 60 ... Load

Claims (5)

A power receiving coil for receiving AC power supplied from a power transmitting device in a contactless manner;
A resonance circuit including the power receiving coil and a resonance capacitor and resonating at a frequency of the AC power;
A diode full-wave rectifier circuit that inputs AC power from the resonance circuit to the first and second input terminals and outputs DC power between the output terminal and the reference potential terminal;
Including a first coil and a second coil wound in the same direction in the same direction in parallel on a common magnetic body, and connecting one end of the first coil to the output end of the diode full-wave rectifier circuit; A common mode filter having one end of the second coil connected to the reference potential end;
A smoothing capacitor connected between the other end of the first coil of the common mode filter and the other end of the second coil;
A load connected in parallel to the smoothing capacitor;
A non-contact power receiving apparatus. A power receiving coil for receiving AC power supplied from a power transmitting device in a contactless manner;
A resonance circuit including the power receiving coil and a resonance capacitor and resonating at a frequency of the AC power;
A diode full-wave rectifier circuit that inputs AC power from the resonance circuit to the first and second input terminals and outputs DC power between the output terminal and the reference potential terminal;
It includes first to fourth coils wound in the same direction in the same direction in parallel with a common magnetic material, and anodes are respectively connected to the first and second input terminals of the diode full-wave rectifier circuit. The first coil and the second coil are disposed in a current path between each cathode of the first and second diodes and the output terminal, and the first and second coils of the diode full-wave rectifier circuit are arranged. Common mode filter in which the third coil and the fourth coil are arranged in the current path between the anodes of the third and fourth diodes, each of which has a cathode connected to the input terminal of 2 and the reference potential terminal When,
A smoothing capacitor connected between the output terminal and the reference potential terminal;
A load connected in parallel to the smoothing capacitor;
A non-contact power receiving apparatus. A power receiving coil for receiving AC power supplied from a power transmitting device in a contactless manner;
A resonance circuit including the power receiving coil and a resonance capacitor and resonating at a frequency of the AC power;
A diode full-wave rectifier circuit that inputs AC power from the resonance circuit to the first and second input terminals and outputs DC power between the output terminal and the reference potential terminal;
It includes first and second coils wound in the same direction by the same number of turns in parallel on a common magnetic material, and anodes are respectively connected to the first and second input terminals of the diode full-wave rectifier circuit. Current paths between the cathodes of the first and second diodes and the output terminal, and third and third cathodes connected to the first and second input terminals of the diode full-wave rectifier circuit, respectively. A common mode filter in which the first coil and the second coil are arranged in at least one current path between each anode of a fourth diode and the reference potential end;
A smoothing capacitor connected between the output terminal and the reference potential terminal;
A load connected in parallel to the smoothing capacitor;
A non-contact power receiving apparatus.   The common mode is provided in each of current paths between the cathodes of the first and second diodes and the output terminal, and current paths between the anodes of the third and fourth diodes and the reference potential terminal. The non-contact power receiving apparatus according to claim 3, wherein the first coil and the second coil of the filter are arranged.   One of a current path between each cathode of the first and second diodes and the output terminal, and a current path between each anode of the third and fourth diodes and the reference potential terminal The non-contact power receiving apparatus according to claim 3, wherein the first coil and the second coil of the common mode filter are arranged in a current path.

Images